[BUG] 2.0.9.2 PID

[rq3]

Did you test the latest bugfix-2.0.x code?

Yes, and the problem still exists.

Bug Description

2.0.9.2 will not settle on a hot end temp. PID settings does not fix the issue.

Bug Timeline

new with release 2.0.9.2. OK with 2.0.9.0

Expected behavior

Temps should settle

Actual behavior

Temps wander rapidly, and will not settle at assigned value. Print will not start.

Steps to Reproduce

Compile and install Marlin 2.0.9.2 using released version and examples.

Version of Marlin Firmware

2.0.9.2

Printer model

Anycubic Predator

Electronics

stock Trigorilla Pro

Add-ons

No response

Bed Leveling

No response

Your Slicer

No response

Host Software

No response

Additional information & file uploads

Attached are screen shots of the effect from Repetier Host
Temp_Compare.docx

[KayIO]

+1
On Trigorilla Pro board. the temperatures are instantly jumping +/- 5 ...therefore the print will not start due to missing settled temprature.
Works fine up to 2.0.9.1 ... but not in 2.0.9.2.

[Alexgrosy]

+1
Same issue here with Trigorilla Pro. Temperature reading of hotend is totaly going nuts in 2.0.9.2.
2.0.9.1 is good.

[ellensp]

If you enable SHOW_TEMP_ADC_VALUES and watch temperature in a console, does the raw ADC values also jump around?

[Alexgrosy]

Just checked with latest bugfix code. The raw ADC values are equally jumpy.
https://pastebin.com/ECveATw7

[github-actions]

This issue has had no activity in the last 60 days. Please add a reply if you want to keep this issue active, otherwise it will be automatically closed within 10 days.

[rq3]

Problem still exists as of January 14, 2022 bugfix. Applies to both user interfaces ( classic and color ui), and is particularly bad with any RTD (platinum resistance sensors) where temps and ADC readings jump as much as +/- 15C between readings.

Appears to be an ADC issue with low impedance sensors? Perhaps lack of oversampling for the RTD routine?

[KayIO]

Problem still exists as of January 14, 2022 bugfix.

Confirmed ! I'm wondering why it worked before, but not now anymore

[Michi1901]

Same here. My PT1000 is reading anywhere within +/- 5C of the target temperature. I am on 2.0.9.2.

[Arakon]

While I'm not seeing jumps that badly, I've been having huge issues with my SKR E3 Mini 2.0 on 2.9.0.3. The temperature is jumping +/- 2° with sometimes unexplained sudden drops by up to 8°, causing a thermal runaway error. 4 out of 5 PID tune runs result in completely bizarre values that cause huge oscillations, too.
The bed is also unstable, but by far not that badly (+/- 0.8°).

2.9.0.3:

I just flashed the BTT 2.8.0.2 Marlin version for an unrelated issue, and all of a sudden, after a single PID tuning run, both bed and hotend are absolutely smooth, bed staying within 0.1°C of the set temperature, hotend within 1°, usually less than 0.5° off.

2.8.0.2:

Note that I'm using the standard MK8 hotend on this printer, with the usual glass bead sensor (Type 1). Both heating cartridge and sensor have been replaced twice, including all wiring, to be sure that it's not a hardware issue.

[Thinkersbluff]

FWIW - I had a problem that sounds like this one, on my CR6-SE, when I flashed a "bugfix"-like developmental version of the CR6Community extui branch, which was recently merged with Marlin 2.9.0.1. I could not get Load Filament to work, and the nozzle temperature was jumping around the target value, seemingly sometimes heating or cooling faster than should be possible.
Reverting to the released v6.1 of that firmware solved the problem.
I have a BTT SKR CR6 v1 board, a PT1000 thermistor and a Dragon HF hotend.

[ceinem]

I'm observing a similar issue on the Anet A8+ with the latest Marlin firmware release.

[descipher]

FWIW - I had a problem that sounds like this one, on my CR6-SE, when I flashed a "bugfix"-like developmental version of the CR6Community extui branch, which was recently merged with Marlin 2.9.0.1. I could not get Load Filament to work, and the nozzle temperature was jumping around the target value, seemingly sometimes heating or cooling faster than should be possible. Reverting to the released v6.1 of that firmware solved the problem. I have a BTT SKR CR6 v1 board, a PT1000 thermistor and a Dragon HF hotend.

Does adding the following to configuration.h change the behavior?
#define ADC_RESOLUTION 10

2.0.9.1 -> 2.0.9.2 ADC resolution changed to 12 bit from 10 bits